Spoilers are typically provided on the upper aerodynamic surface of an aircraft wing, between the main fixed wing box and the trailing edge flaps. The performance of the flaps can be improved by attaching them to the fixed wing box by drop hinge mechanisms. This allows the flaps to be deployed in both aft and downward directions and to be rotated downwardly (or “drooped”). When the flaps are fully deployed in this way, gaps are formed between the trailing edges of the spoilers and the leading edges of the flaps. Small air gaps in these regions improve lift when compared to conventional Fowler flaps. However, if these gaps are too large and the continuity of the upper aerodynamic surface is not maintained, then the performance of the flaps is reduced. To control the size of these gaps, the spoilers are rotated downwardly (or “drooped”) when the flaps are fully deployed (e.g. during take-off).
The spoilers are typically attached to the fixed wing box by structural ribs. Cut-out sections are provided on the leading edges of the spoilers to prevent clashing between the spoilers and the ribs when the spoilers are deployed to a braking position. However, particularly when the spoilers are in their drooped positions, these cut-out sections become exposed. When the flaps are deployed, voids are opened on the high pressure lower surface of the wing. This can lead to cross-bleed air flowing from the high pressure lower surface, through air gaps in the joints between the structural ribs and the spoilers, and through the cut-out sections to the low pressure upper surface. This leads to a reduction in lift. Also, when the spoilers are in their cruise positions, the cut-out sections act as discontinuities in the path of the air flow, increasing drag and noise. Consequently, for optimum performance, these air gaps need to be sealed, while allowing the spoilers to rotate over their entire pivotal range without clashing with the structural rib.